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Abstract:

Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The synthesis, structure, and magnetism of a nonanuclear iron(III) phosphonate, [Fe 9 III (μ 3 -O) 4 (O 3 PC 5 H 9 ) 3 (O 2 CCMe 3 ) 13 ]·(EtOH) 0.5 ·(Et 2 O) 0.5 (1), is described. Compound 1 was obtained in the direct reaction of anhydrous ferric chloride, cyclopentylphosphonic acid, and pivalic acid in the presence of triethylamine. Compound 1 possesses a distorted icosahedral structure; nine of the vertices are occupied by Fe III , whereas three others are occupied by the phosphorus atoms of the cyclopentylphosphonate ligand. Mössbauer spectroscopy of 1 confirms the presence of high-spin Fe III . Low-temperature magnetic studies reveal the presence of strong antiferromagnetic coupling between the Fe 3+ ions. The reaction of anhydrous ferric chloride with cyclopentylphosphonic acid and pivalic acid in the presence of triethylamine at room temperature afforded a nonanuclear iron(III) phosphonate. It possesses a cage structure with a distorted icosahedral core. Mössbauer studies confirm high-spin Fe III , whereas magnetic measurements suggest strong antiferromagnetic couplings between the Fe 3+ ions.

Abstract:

Solid state techniques involving pressure and temperature have been used to synthesize the fluoride member of the CuX2(pyrazine) (X = F, Cl, Br) family of coordination polymers that cannot be crystallized by solution methods. CuF2(pyrazine) exhibits unique trans doubly-bridged Cu-F2-Cu chains that provide an opportunity to quantify magnetic superexchange in an isostructural Cu-X2-Cu series. © 2013 The Royal Society of Chemistry.

Abstract:

CuF(2)(H(2)O)(2)(3-chloropyridine) possesses a five-coordinate Cu(2+) center with a slightly distorted trigonal bypyramidal coordination geometry. Strong intermolecular F···H-O hydrogen bonds enable the formation of 2D layers and provide the primary magnetic exchange path that leads to the stabilization of long-range antiferromagnetic (AFM) order below T(N) = 2.1 K.

Abstract:

Figure Persented: [Ni(HF 2)(3-Clpy) 4]BF 4 (py = pyridine) is a simple one-dimensional (1D) coordination polymer composed of compressed NiN 4F 2 octahedra that form chains with bridging HF 2- ligands. In spite of significant distortion of the HF 2- bridge, a quasi-1D antiferromagnetic (AFM) behavior was observed with J FHF = 4.86 K. © 2012 American Chemical Society.